1. Field of the Invention
The present invention relates to the connection of pipes in a subsea environment. More particularly, the present invention the relates to stab-and-hinge techniques for moving pipes from a vertical orientation to a generally horizontal orientation. The present invention also relates to systems and processes whereby the hubs of respective pipes can be joined together and locked together without human intervention.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Pipes are often used to connect pieces of subsea oilfield equipment for fluid communication. These pipes are somewhat flexible armored hoses or pipes that can be provided with subsea matable connectors at either end. Typically, they are installed by be lowered into place from a pipe laying vessel. The final positioning and makeup of the end connectors is carried out by divers or by an remotely-operated vehicle (ROV). Short diver or ROV-installable hoses and pipes that are used to connect adjacent pieces of subsea equipment are known as jumpers.
Examples of subsea equipment that may be interconnected using such pipes or jumpers include subsea Christmas trees, manifolds and flow control or processing equipment located on the seabed, such as chokes, gas/water separators, pumps and gas liquification plants.
Where there are several different pieces of equipment to be interconnected, the installation of the pipes can be relatively time-consuming. An end of the pipe is generally lowered vertically toward the seabed from a pipe-laying vessel. The pipe is then laid out horizontally between the points to be interconnected. The pipe ends must then be retrieved from the seabed bed by a diver or an ROV. The end connectors are then aligned with the subsea equipment or with an adjacent pipe for make-up of the required fluid-tight connections.
In the past, various pieces of subsea equipment have generally vertical pipes extending therefrom. When the pipes are in a generally vertical orientation, a pipe can be lowered downwardly from the surface of the body of water so that the end can be aligned with the vertical pipe and joined thereto. The process of connection becomes much more complicated when it is desired to achieve a horizontal connection between the respective pipes and connectors. Typically, horizontal connections are very useful in those circumstances when there are height restrictions or other interferences to proper connections.
In the past, techniques have been provided for horizontally joining pipes in the subsea equipment. The equipment used to achieve such connections has been very complicated, expensive, and cumbersome. As such, a need has developed so as to provide a system which can be easily adapted for the connection of subsea pipes in the generally horizontal orientation. Additionally, there is a need so as to provide such equipment whereby the equipment can remain on the seabed after installation. As such, the relative cost associated with such apparatus should be relatively minimal.
In the past, various patents have issued relating to the connection of horizontal pipes. For example, U.S. Pat. No. 4,294,471, issued on Oct. 13, 1981 to van Bilderbeek, discloses a subsea flowline connector for connecting a horizontal flowline on a seabed to a vertical riser. A flowline flange on the end of the flowline is held in a preselected location while a rigid tubular spool piece is stroked into sealing relationship therewith. The spool piece is rigid and has horizontally and vertically extending portions. The spool piece is guided so that the entire spool piece moves with the stroking and the vertical stab with the riser is made after the sealing stroke is effected.
U.S. Reissue Pat. No. 31,265, reissued on Jun. 7, 1983 to Sinclair et al., provides a method and apparatus for making subsea pipe connections. A subsea pipeline hub is connected to the hub of an adjacent spool piece connected to an in-place manifold of a subsea structure that is used in the production of oil and/or gas. The pipeline hub is positioned relative to the opposing spool hub and a remotely-operated pipeline connecting tool is lowered from the water's surface to the subsea structure using guidelines and structural guidance for alignment of the pipeline hub with the spool piece hub. The spool piece hub is then drawn to the pipeline hub and the hubs are clamped together by operation of the connecting tool. Connecting tool operations are powered by hydraulic fluid and controlled from the surface. The pipeline hub may be lowered vertically and pivoted into its position adjacent the spool piece or may be pulled into that position.
U.S. Pat. No. 4,886,395 issued on Dec. 12, 1989 to Moles et al., teaches a pipeline-to-riser connection method and apparatus for remotely connecting an offshore structure to an underwater pipeline using an ROV. The structure has a bell-mouthed bending guide at its base through which a winch line from the surface passes and is temporarily looped back and attached to an accessible place on the structure. The pull-in line is attached to a terminal assembly at the end of flexible pipe attached to the pipeline. The terminal assembly is pulled in horizontally to the guide, arcuately through the guide, and then from the guide into general vertical alignment with a pipe end receiver assembly on the structure above the bending guide.
U.S. Pat. No. 5,730,551, issued on Mar. 24, 1998 to Skeels et al., provides a subsea connector system and method for coupling subsea conduits. This method utilizes a skid on the sea floor for coupling a subsea conduit carried by the skid to a subsea conduit on a relatively fixed subsea structure. A lift line device or structure has an upper lift line connected by a spreader bar to a pair of lower guide lines which are directed from a vertical position to a generally horizontal position by J-tubes. The ends of the guide lines have anchor members thereon which are anchored to guides on the subsea facility. Upon raising of the upper lift line, the skid moves in a combined pulling and lifting motion to engage a side of the subsea facility for being guided into a docked position with aligned guides on the subsea facility. In this position, an ROV secures the skid into a releasably locked position by insertion of retainer pins into aligned openings of the skid and subsea facility. The coupling on the end of flowline conduit is coupled onto an aligned conduit on the subsea facility.
U.S. Pat. No. 6,142,708, issued on Nov. 7, 2000 to Tarlton et al., provides a rotating porch for subsea branch and termination pipeline connections. A landing platform and swivel connection hub are attached to a pipeline branch, termination, or manifold. The landing platform is mounted so that it may be rotated about the connection hub. This permits the installation of the subsea connection on a near level platform and allows the pipeline to be laid subsea with greater roll angles than would be acceptable otherwise. The elevation of the platform is adjusted by an ROV and locked into place once the adjustment is completed.
U.S. Pat. No. 6,481,504, issued on Nov. 19, 2002 to N. Gatherar, shows a flowline connector with a subsea equipment package. The flowline connector has a first connector portion for mounting on a first piece of subsea equipment. A second connector portion of the flowline connector is attached to an end portion of a flowline. Each connector portion has a respective guide interengageable by lowering the second connector portion, on the end portion of the flowline, into the first connector portion. The guides allow the second connector portion to pivot relative to the first connector portion to bring the first connector portion and the second connector portion into axial alignment for make-up of a fluid-tight connection therebetween.
U.S. Pat. No. 7,794,177, issued on Sep. 14, 2010 to K. DeLack, discloses a subsea system for securing an end portion of a pipeline. A subsea foundation has a lower portion located below the sea floor and an upper portion extending above the sea floor. The subsea foundation has a receptacle formed in the upper portion. The system includes a base frame that lands on the subsea foundation. The base frame has a track formed therein. A stab is hingedly mounted to the base frame. The stab stabs into the receptacle to secure the base frame to the subsea foundation. A sliding mechanism is carried by the base frame and moves along the track. The sliding mechanism is connected to a segment of the pipeline extending along the sea floor.
U.S. Pat. No. 8,057,126, issued on Nov. 15, 2011 to Mogedal et al., provides a connector means for tie-in and connecting of a first pipeline and a second pipeline. The connector means includes a first connector part retaining a first end of the first pipeline. The first connector part and the first pipeline are designed to be lowered and deployed on the seabed in advance of the connecting operation. A submersible second connector part that retains a second end of the second pipeline is also included. The second connector part and the second pipeline are designed to be lowered from the surface of the water toward the first connector part. The connector parts include means that cooperate during relative motion between the connector parts. The second connector part is hingedly tiled by means of forced motion. This aligns the second pipe end in the direction toward the first pipe end such that the first and second pipelines are brought to be in line with each other on the seabed.
It is an object of the present invention to provide a subsea pipe connection system which effectively establishes horizontal connections between pipes.
It is another object of the present invention to provide a subsea pipe connection system that avoids height restrictions that would affect vertical pipes.
It is another object of the present invention to provide a subsea pipe connection system which is allows the pipes to be relatively easily connected.
It is another object of the present invention to provide a subsea pipe connection system which is extremely reliable.
It is a further object of the present invention to provide a subsea pipe connection system which allows certain components to remain on the seabed following the connection of the pipes to one another.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.